Over the past year, fund managers including Loomis Sayles & Co. and Chicago-based Harbor Capital Advisors Inc. have opened funds that employ a so-called "go-anywhere" approach to better deal with risks such as rising interest rates.

Having that kind of flexibility gives go-anywhere funds the ability to "cover a lot of ground that I can't," says veteran financial planner Vern Hayden, who says he doesn't have the resources to stay on top of so many markets and regions.